I have been running LR 4 for several weeks and all of a sudden my photos will look one way in the Develop Module and then look muted in the Library Module. I was working on a test photo of my wife yesterday and got the colors just right in the Develop Module, when I switched back to Library it looked as iff someone had turned down the saturation by 25%. I got two other people to look at it and they saw the same thing. I have been using LR since it first came out and have never seen anything like this. Anyone have any ideas on why this would happen. It has nothing to do with the process either... on FB I asked the same question is a photography group and all that they could come up with was to make sure I was in Process 2012.

Is your monitor calibrated and profiled? Could anything have changed with the monitor profile?

In Develop module, LR is working on the image in ProPhoto RGB working space, and renders images in that colour space.

In Library module, LR shows you previews which are on Adobe RGB.

Provided the monitor profile is OK, this won't matter: what is displayed on the monitor (with colour management) will be the same in each module. I'm not quite sure what's happening here; you can't turn off colour management in LR - but even if you could, without colour management the RGB values for ProPhoto (Develop module) would look less saturated than the RGB values for the same image in Adobe RGB.

However, my first guess would be a colour management problem. Check the monitor profile. If you have a hardware device (Spyder, ColorMunki etc) then recalibrate the monitor. If you don't, see if a profile was supplied with the monitor, and check that's applied by Windows (Control Panel, Color Management - don't know how on a Mac). If there isn't a profile with the monitor, try assigning the sRGB profile to the monitor (it's called sRGB IEC something-or-other). This won't be the right profile for sure, but see if it makes the problem go away, in which case you know you've got a monitor profile problem.

I also have a serious problem with Lightroom 4. Images look perfect in Develop module, but looks noisier and out of focus in Library module. Hence, the exported ones will be affected in the same way. I tried to adjust the render previews as suggested by some forums but it didn't work. I never had a problem like this and this will make Lighroom useless in sharpening images.

I calibrate my monitors every few days with the X-rite Dispaly Pro something or other. It was not a calibration issue... the differences were seen on the same monitor. I did not realise that the develop module and the library module use different color spaces... that makes no sense to me at all.

After putting the computer offline for 24 hours (turned off and unplugged) then rebooting AND downloaded and installed LR4.1 the problem seems to have gone away... although the develop module remains painfully slow... although it is somewhat better in 4.1 than in 4.0 but still slower than 3.6!

I have also seen this occur in v3.6 on a Mac; quitting LR and re-starting always solves the problem. It seems that there may be a memory leak, and when it gets bad, LR starts to lose track of what changes have been made to a file while in grid mode in the Library module (I've seen crops rotated wrong, etc.).

This problem looks similar to one I have encountered with LR4. I have been working with large panoramic files formed by stitching 4 images together, eg 9200 x 2130 pixels. After I have adjusted colour, contrast and sharpening in the the Develop module, I find that when I switch back to Library the image is blurred, although colour settings look OK. It turns out that this happens when the Zoom setting in the Loupe view is set to 'Fill'. If I adjust the Zoom slider in the tool bar I can keep the image sharp at all magnifications, but it blurs as soon as I go back to 'Fill'.

I have not seen this problem with 'regular' images, so it looks as though it could be related to the file size. Re-starting LR or re-booting the PC do not have any effect. I have 8 GB Ram in my PC, which should be enough to keep me out of trouble.

it is apparently a common error with the last updates of Lightroom and Adobe should do some thing to resolve this. Otherwise, Lightroom is destroying my images.

I don't think I understand your problem. How is Lightroom destroying your images?

I read your previous posts, including the comment "I also have a serious problem with Lightroom 4. Images look perfect in Develop module, but looks noisier and out of focus in Library module. Hence, the exported ones will be affected in the same way.", which does not relate to the way Lightroom works for me.

it is apparently a common error with the last updates of Lightroom and Adobe should do some thing to resolve this. Otherwise, Lightroom is destroying my images.

I doubt that will happen. Different people seem to be seeing slightly different things in this thread; the common feature is a different appearance of the image when going from the Develop module to the Library module. In my own case it only seems to happen with stitched images (around 9000 pixels wide) but independently of the stitching software used. The images export correctly and the exported images show no sign of the blurring seen in the LR Library module. I tried creating a large image by resizing a file to 9000 x 9000 pixels, imported into LR4, tweaked in the Develop module and then examined it in the Library module. No sign of a problem!

Whatever is going on looks more like an annoyance than a catastrophe, but an annoyance I would rather do without. The one unpleasant possibility is that it may indicate something more serious lurking deep in the software.